共查询到20条相似文献,搜索用时 31 毫秒
1.
J. H. Lee J. S. Kim K. H. Cho J. Ch. Woo M. S. Han Y. S. Chung 《Journal of Radioanalytical and Nuclear Chemistry》1998,234(1-2):77-83
Trace impurity elements in high purity copper metal (4 mine class) put on the market were analyzed by Instrumental Neutron
Activation Analysis (INAA) and the results compared with those from Graphite Furnace Atomic Absorption Spectrophotometry (GFAAS)
and Inductively Coupled Plasma Atomic Emission Spectrophotometry (ICP-AES). The sample irradiation was done at the irradiation
facilities (thermal neutron flux, 5·1012 n·cm−2·s−1) of the TRIGA Mark-III research reactor in the Korea Atomic Energy Research Institute. Four unalloyed copper standards (NIST
SRM # 393, 394, 395 and 398) were used to identify the accuracy and precision of the analytical procedure. The homogeneity
of samples was assessed by means of the elements such as Ag, As, Co, Sb, Se and Zn. The analytical results of INAA, GFAAS
and ICP-AES were in good agreement within expected uncertainties each other and showed the possibility of using them for the
analytical quality control. 相似文献
2.
P. K. Nayak B. Wierczinski S. Lahiri 《Journal of Radioanalytical and Nuclear Chemistry》2008,278(1):179-184
Representative banded iron-formations (BIFs) from various locations of the eastern Indian geological belt were investigated
by instrumental neutron activation analysis (INAA). After pre-concentration, irradiation was carried out using a neutron flux
of 5.1·1016 m−2·s−1, 1.0·1015 m−2·s−1 and 3.7·1015 m−2s−1, with thermal, epi-thermal and fast neutrons, respectively. The activities in these samples were measured by a HPGe detector.
Ten rare-earth elements, such as La, Ce, Nd, Sm, Eu, Tb, Ho, Tm, Yb and Lu, have been qualitatively identified and quantitatively
estimated in these samples. The present investigation is an example of employing a pre-concentration method for high iron-containing
ores prior to neutron activation analysis. 相似文献
3.
I. P. Alimarin A. Z. Miklishanskii Yu. V. Yakovlev 《Journal of Radioanalytical and Nuclear Chemistry》1970,4(1):45-51
A method with a sensitivity of 2·10−7 to 1·10−10% has been developed for determining Yb, Ho, Dy, Gd, Eu, Sm and La impurities in metallic uranium by means of neutron activation.
The method is based on a preliminary chromatographic separation of the total amount of rare earth elements from uranium by
passing the solution in sulphuric acid through KU-2 cation exchange resin and eluting the traces of uranium retained by the
resin with a solution of ascorbic acid. The rare earth impurities are then eluted from the resin with 4–5N HCl, evaporated, and irradiated for 20 hours with a neutron flux of 1.2·1013 n·cm−2·sec−1. Subsequently the traces of the rare earth elements are co-precipitated with Fe(OH)3, dissolved in concentrated HCl and separated from the iron and other impurities by passing the solution through Dowex 1X8
anion exchange resin in the chloride form. The individual rare earth elements are then separated from each other using KU-2
cation exchange resin and a solution of ammonium α-hydroxyisobutyrate as the eluant. 相似文献
4.
5.
A. Gaudry B. Maziere D. Comar D. Nau 《Journal of Radioanalytical and Nuclear Chemistry》1976,29(1):77-87
For the simultaneous determination of many elements in small biological samples, a multi-element analysis has been developed
using neutron activation. After a 24-hr irradiation in a neutron flux of 2.5·1014 n·cm−2·sec−1 and after immediate chemical separation without cooling, it was possible to analyse 24 elements in bovine liver (NBS-SRM
1577). The separation apparatus, set up in a shielded cell can work four samples simultaneously, and its operation is fast
enough to allow the detection of radioisotopes with a half-life of about 2 hrs (165Dy,57mSr,56Mn). Amounts lower than 10−3 μg of Dy, Eu, Pr, Sm and Yb were determined. 相似文献
6.
A method was developed for the determination of 15 trace elements in tin. High-purity tin samples (99.9999% and 99.999%) as
well as tin of technical quality were analysed. Reactor neutron activation of the tin samples was followed by distillation
of the matrix activities from a HBr−H2SO4 medium and Ge(Li) gamma-ray spectrometry of the distillation residue. The sensitivity of the method is generally high. For
the high-purity samples the detection limits vary from 0.02 ppb (scandium) to 200 ppb (iron) for irradiation of 1 g of tin
for 1 week at a thermal flux of 5·1012n·cm−2. ·sec−1. To decontaminate the surface of the tin samples, pre- and post-irradiation etching procedures were applied. The efficiency
of these etching techniques was studied. 相似文献
7.
An instrumental neutron activation analysis (INAA) method has been developed for multi-element determination in geological
samples. The INAA method consists of irradiation of samples for 90 sec at a flux of 1.0·1012 n·cm−2·sec−1 and determination of 12 elements by using their short-lived nuclides. Samples have been re-irradiated for 3 hrs for measuring
concentrations of another 10 elements. Precision and accuracy of the INAA method have been evaluated by analysing samples
and USGS standard reference materials. Precision and accuracy are within±15% and ±10%, respectively. 相似文献
8.
S. P. Mishra D. Tiwari S. K. Prasad R. S. Dubey M. Mishra 《Journal of Radioanalytical and Nuclear Chemistry》2007,272(2):371-379
The role of dead biomasses viz., mango (Mangifera indica) and neem (Azadirachta indica) bark samples are assessed in the removal behavior of, one of important fission fragments, Cs(I) from aqueous solutions employing
a radiotracer technique. The batch type studies were carried out to obtain various physico-chemical data. It is to be noted
that the increase in sorptive concentration (from 1.0·10−8 to 1.0·10−2 mol·dm−3), temperature (from 298 to 328 K) and pH (2.6 to 10.3) apparently favor the uptake of Cs(I) by these two bark samples. The
concentration dependence data obeyed Freundlich adsorption isotherm and the uptake follows first order rate law. Thermodynamic
data evaluation and desorption experiments reveal the adsorption to be irreversible and endothermic in nature proceeding through
ion-exchange and surface complexation for both dead biomasses. Both bark samples showed a fairly good radiation stability
in respect of adsorption uptake of Cs(I) when irradiated with a 300 mCi (Ra-Be) neutron source having an integral neutron
flux of ∼3.85·106 n·cm−2·s−1 and associated with a nominal γ-dose of ∼1.72 Gy·h−1. 相似文献
9.
A preliminary study to evaluate the use of neutron activation analysis for the characterization of six groups of man-made
fibers for forensic purposes has been made. A total of 81 samples of acetate, acrylic, modacrylic, nylon, polyester and rayon
were analyzed. Small samples, approximately the size typically found during a crime scene search, were analyzed using a Ge(Li)
detector system following a 20 min irradiation at a flux of 5·1013 n·cm−2·sec−1. The following elements were determined quantitatively in one or more of the samples: Ti, Sr, Au, Zn, Sb, Br. Mn, Mg, Cu,
In, Co, Cu, V, K, Al, Cl, Na, Ca, and S. Significant qualitative and quantitative differences were found both between and
within the six groups. However, within certain groups some fibers from different manufacturers showed marked similarities
in qualitative and quantitative composition. 相似文献
10.
A. Godelitsas M. Kokkoris P. Misaelides 《Journal of Radioanalytical and Nuclear Chemistry》2007,271(2):339-344
To enhance the applicability of the nuclear analytical technique in the field of industry and the environment, the inorganic
elemental content of the bottom ash from a municipal solid waste incinerator was determined by instrumental neutron activation
analysis. Bottom ash samples were monthly collected from an incinerator located at a metropolitan city in Korea, strained
through a 5 mm sieve, dried by an oven and pulverized by an agate mortar. The samples were irradiated at the NAA #1 irradiation
hole (thermal neutron flux: 2.92·1013 n·cm−2·s−1) in the HANARO research reactor of the Korea Atomic Energy Research Institute and the irradiated samples were measured by
a HP Ge gamma-ray spectrometer. Thirty-three elements including As, Cr, Cu, Fe, Mn, Sb and Zn were analyzed by an absolute
method. The quality control was conducted by a simultaneous analysis with NIST standard reference materials. The average concentrations
of the major elements such as Ca, Fe, Al, Na, Mg, K and Ti measured in the sample were 19.9%, 4.85%, 3.79%, 2.11%, 1.84%,
1.22% and 1.02%, respectively. In addition, the concentrations of the hazardous metals like Zn, Cu, Cr, Sb and As were 0.77%,
0.31%, 729 mg·kg−1, 116 mg·kg−1 and 22.2 mg·kg−1, respectively. 相似文献
11.
T. Fujinaga Y. Kusaka M. Koyama H. Tsuji T. Mitsuji S. Imai J. Okuda T. Takamatsu T. Ozaki 《Journal of Radioanalytical and Nuclear Chemistry》1973,13(2):301-311
A method is described for the determination of trace metal ions, V, Al, Cu, Mo Zn, and U, in natural water samples by neutron
activation analysis, using organic coprecipitation as a preconcentration method. The preconcentration of trace elements was
accomplished by converting the dissolved trace metal ions into the oxine chelates atpH 5.2 and extraction of the chelates witho-phenylphenol which is a liquid above 56 °C and solidifies at room temperature. After cooling the extraction system, the fine
particles of the organic phase were collected on a millipore filter and the precipitate was air-dried in a clean environment.
The solid extract was wrapped up in a sheet of clean polyethylene and subjected to neutron irradiation in a reactor for less
than 10 min at a thermal flux of 2·1013 n·cm−2·sec−1. γ-Ray spectrometry by a coaxial Ge(Li) detector connected to a 1024-channel PHA was performed on the irradiated sample without
further chemical separation, and thus the ppb level concentration of the elements in natural water samples could be determined.
The fundamental study of the collection of the trace elements is also described. 相似文献
12.
H. -U. Fanger R. Pepelnik W. Michaelis 《Journal of Radioanalytical and Nuclear Chemistry》1981,61(1-2):147-163
At the GKSS Research Center Geesthacht, a new 14 MeV activation facility—a 5·1012 n/s neutron generator combined with a fast rabbit system (KORONA)—is being installed. Homogeneous neutron flux at a level
of 5·1010 n·cm−2·s−1 and sample transfer times of 140 ms to a 16m distant detector station are characteristic features of the facility described
in the paper. With special consideration of short-lived nuclides and including cyclic activation, the analytical prospects
with the intense neutron source are discussed, and sensitivities for 78 elements are presented. 相似文献
13.
The use of 2.8 MeV neutrons produced by the D(d, n)3He reaction should be taken into consideration in some applications of radioactivation analysis. The low number of elements
activable by these neutrons makes possible to minimize the matrix interference and the background below the characteristic
photopeaks. The very low dead-time of the spectrometric measurements permits the use of the maximum neutron flux available
now and in the future. The purpose of this paper is to define experimentally the sensitivity of determination for the 16 main
elements activable with a 400 keV Van de Graaff accelerator at a 2.8 MeV neutron flux of 2·106 n·cm−2·sec−1 on the sample. 相似文献
14.
I. P. Alimarin Yu. V. Jakovlev A. Z. Miklishansky N. N. Dogadkin O. V. Stepanets 《Journal of Radioanalytical and Nuclear Chemistry》1968,1(2):139-145
Radioactivation analysis is the only method which allows the determination of individual rare earth element impurities in
rare earth elements of high purity. The determination of dysprosium, europium, samarium and gadolinium in yttrium oxide is
complicated by the short half-life of165Dy (138 min.) and by the difficulty of separating traces of these elements from the matrix. A chromatographic method has been
developed, for the separation of traces of Dy, Eu, Sm and Gd from ytrium, on a column packed with anion exchangerAV-17, by means of elution with 0.1N and 0.3M solutions of EDTA-sodium salt, followed by the separation of the mixture of the rare earth impurities on a microcolumn of
cation exchangerKU-2, using a 0.17M solution of ammonium α-hydroxyisobutyrate as the eluent. The sensitivity of the determination of Dy, in the case of irradiating
10 mg of Y2O3 with a flux of 1.2·1013 n·cm−2·sec−1 for 5 min. was 1·10−7%; the corresponding values for Sm, Eu and Gd, when irradiating a 100 mg sample of Y2O3 for 20 hours with the same flux, were 2·10−7%, 1·10−8% and 5·10−6%, respectively. 相似文献
15.
A collimated neutron beam capable of providing a thermal neutron flux of 4.75·107 n·cm−2·sec−1 has been used to analyze alloy samples of 1–5 g during relatively short irradiation times of 30 min by the use of neutron
capture gamma-ray spectrometry. The analyses were performed by using a mathematical treatment that relates the count ratio
of every constituent present in the matrix with the concentration and thus it requires no standards. The technique was applied
to the analysis of steel and gold alloy samples. Errors ranged from 0.8%–10%. 相似文献
16.
Certain elements which are not possible to detect with conventional neutron activation analysis can be measured using thermal
neutron-capture gamma-ray analysis. The use of a curved neutron guide at the High Flux Reactor, Grenoble, with a thermal neutron
flux of 1.5·1010n·cm−2·sec−1 and the advantage of a low-background counting system (Ge(Li) detector) far from the reactor core are described. Experimental
detection limits of a number of elements are given for the low-energy and the high-energy regions. Some applications of the
capture gamma-ray method in the whole energy range are studied and are briefly discussed. 相似文献
17.
A sensitive, simple and time-saving method has been developed for the neutron activation analysis of gallium at concentrations
around 10−4 ppm in biological tissues. After a 24-hour irradiation in a thermal neutron flux of 2.8·1013 n·cm−2·s−1 and a purification by ion-exchange chromatography to eliminate troublesome elements such as sodium, iron and copper, the72Ga activity is measured with enough accuracy for the method to be applicable in animal physiology and clinical toxicology. 相似文献
18.
N. N. Dogadkin O. I. Kychinskaya V. I. Tustanovsky Yu. V. Yakovlev 《Journal of Radioanalytical and Nuclear Chemistry》1976,29(2):251-258
A procedure for neutron-activation analysis of cerium, lanthanum, praseodymium and neodymium, tested on more than thirty samples
of steels, is described. After irradiation for 20 hrs with a neutron flux of 1.2·1013 n·cm−2·sec−1 the steel samples were dissolved in aqua regia and extraction separation of iron from 6N HCl by ether was employed. The REE
were separated as a group by precipitation as fluorides and hydroxydes. The individual rare-earth elements were separated
from each other using a KU-2 cation exchange resin and a solution of ammonium α-hydroxyisobutirate as eluant. The separated
samples were counted on a NaI(T1) γ-spectrometer. 相似文献
19.
S. S. Nargolwalla J. Niewodniczanski J. E. Suddueth 《Journal of Radioanalytical and Nuclear Chemistry》1970,5(2):403-423
The experimental sensitivity for 72 different elements using 3 MeV neutron activation has been investigated. Using a 200 kV
Cockcroft-Walton neutron generator with a 3 MeV neutron flux of about 1.5·106n·cm−2·sec−1, γ-ray spectra of 51 elements were obtained with a sufficient number of photopeak counts for sensitivity calculations using
a photopeak integration method. A useful table summarizing the sensitivity results is given. That 3 MeV neutron activation
analysis is practical, is demonstrated by the experimental sensitivities obtained.
Guest worker from the Institute of Nuclear Techniques, Academy of Mining and Metallurgy, Krakow, Poland, at the National Bureau
of Standards, 1968–1969. 相似文献
20.
F. Z. Khiari A. Aksoy A. Sahin 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(3):507-511
Extensive sedimentary phosphate deposits exist in the Sirhan-Turayf basin in northwestern Saudi Arabia containing significant
amounts of uranium, thorium, vanadium and rare earth elements. The determination of the concentration and pattern of distribution
of some of these elements is essential for economic aspects. This study reports the analysis of vanadium in selected phosphate
rock samples from the basin using accelerator-based thermal neutrons activation analysis (TNAA). Samples were irradiated in
a thermal neutron flux of 2.5·106 n·cm−2·s−1. The induced activity was measured with a HP-GMX detector coupled to a PC-based data acquisition and analysis system. The
facility was calibrated using certified standards of vanadium. The minimum detection limit of vanadium was about 1 mg. Three
independent measurements on each sample yielded comparable results indicating the reliability of the technique. The vanadium
concentrations in the samples vary from 23 to 457 ppm.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献